1.
Biochemistry (journal)
–
Biochemistry is a peer-reviewed academic journal in the field of biochemistry. Founded in 1962, the journal is now published weekly by the American Chemical Society, the journals 2014 impact factor was 3.015, and it received a total of 90,842 citations in 2012. The editor-in-chief was Richard N. Armstrong, after his death, Alanna Schepartz was appointed editor-in-chief. Biochemistry is indexed in, Biochemistry website NCBI, Biochemistry
2.
Biomolecule
–
A more general name for this class of material is biological materials. Biomolecules are usually endogenous but may also be exogenous, for example, pharmaceutical drugs may be natural products or semisynthetic or they may be totally synthetic. Biology and its subsets of biochemistry and molecular biology study biomolecules, most biomolecules are organic compounds, and just four elements—oxygen, carbon, hydrogen, and nitrogen—make up 96% of the human bodys mass. But many other elements, such as the various biometals, are present in small amounts, examples of these include cytidine, uridine, adenosine, guanosine, thymidine and inosine. Nucleosides can be phosphorylated by specific kinases in the cell, producing nucleotides, both DNA and RNA are polymers, consisting of long, linear molecules assembled by polymerase enzymes from repeating structural units, or monomers, of mononucleotides. DNA uses the deoxynucleotides C, G, A, and T, while RNA uses the ribonucleotides C, G, A, modified bases are fairly common, as found in ribosomal RNA or transfer RNAs or for discriminating the new from old strands of DNA after replication. Each nucleotide is made of a nitrogenous base, a pentose. They contain carbon, nitrogen, oxygen, hydrogen and phosphorus and they serve as sources of chemical energy, participate in cellular signaling, and are incorporated into important cofactors of enzymatic reactions. DNA structure is dominated by the double helix formed by Watson-Crick base-pairing of C with G and A with T. This is known as B-form DNA, and is overwhelmingly the most favorable and common state of DNA, its highly specific and stable base-pairing is the basis of reliable genetic information storage. DNA can sometimes occur as single strands or as A-form or Z-form helices, RNA, in contrast, forms large and complex 3D tertiary structures reminiscent of proteins, as well as the loose single strands with locally folded regions that constitute messenger RNA molecules. Those RNA structures contain many stretches of A-form double helix, connected into definite 3D arrangements by single-stranded loops, bulges, examples are tRNA, ribosomes, ribozymes, and riboswitches. Monosaccharides are the simplest form of carbohydrates with only one simple sugar and they essentially contain an aldehyde or ketone group in their structure. The presence of an group in a monosaccharide is indicated by the prefix aldo-. Similarly, a group is denoted by the prefix keto-. Examples of monosaccharides are the hexoses glucose, fructose, and galactose and pentoses, ribose, most saccharides eventually provide fuel for cellular respiration. Disaccharides are formed when two monosaccharides, or two simple sugars, form a bond with removal of water. They can be hydrolyzed to yield their saccharin building blocks by boiling with dilute acid or reacting them with appropriate enzymes, examples of disaccharides include sucrose, maltose, and lactose
3.
Metabolism
–
Metabolism is the set of life-sustaining chemical transformations within the cells of living organisms. These enzyme-catalyzed reactions allow organisms to grow and reproduce, maintain their structures, usually, breaking down releases energy and building up consumes energy. The chemical reactions of metabolism are organized into metabolic pathways, in one chemical is transformed through a series of steps into another chemical. Enzymes act as catalysts that allow the reactions to proceed more rapidly, enzymes also allow the regulation of metabolic pathways in response to changes in the cells environment or to signals from other cells. The metabolic system of a particular organism determines which substances it will find nutritious, for example, some prokaryotes use hydrogen sulfide as a nutrient, yet this gas is poisonous to animals. The speed of metabolism, the rate, influences how much food an organism will require. A striking feature of metabolism is the similarity of the metabolic pathways. These striking similarities in metabolic pathways are likely due to their appearance in evolutionary history. Most of the structures that make up animals, plants and microbes are made from three classes of molecule, amino acids, carbohydrates and lipids. These biochemicals can be joined together to make such as DNA and proteins. Proteins are made of amino acids arranged in a linear chain joined together by peptide bonds, many proteins are enzymes that catalyze the chemical reactions in metabolism. Other proteins have structural or mechanical functions, such as those that form the cytoskeleton, Proteins are also important in cell signaling, immune responses, cell adhesion, active transport across membranes, and the cell cycle. Lipids are the most diverse group of biochemicals and their main structural uses are as part of biological membranes both internal and external, such as the cell membrane, or as a source of energy. Lipids are usually defined as hydrophobic or amphipathic biological molecules but will dissolve in organic solvents such as benzene or chloroform, the fats are a large group of compounds that contain fatty acids and glycerol, a glycerol molecule attached to three fatty acid esters is called a triacylglyceride. Several variations on this structure exist, including alternate backbones such as sphingosine in the sphingolipids. Steroids such as cholesterol are another class of lipids. Carbohydrates are aldehydes or ketones, with hydroxyl groups attached. Carbohydrates are the most abundant biological molecules, and fill numerous roles, such as the storage and transport of energy, the basic carbohydrate units are called monosaccharides and include galactose, fructose, and most importantly glucose
4.
History of biochemistry
–
The term “biochemistry” itself is derived from the combining form bio-, meaning life, and chemistry. Nevertheless, several sources cite German chemist Carl Neuberg as having coined the term for the new discipline in 1903, and some credit it to Franz Hofmeister. Over the last 40 years the field has had success in explaining living processes such that now almost all areas of the life sciences from botany to medicine are engaged in biochemical research. Among the vast number of different biomolecules, many are complex and large molecules, each class of polymeric biomolecule has a different set of subunit types. Biochemistry studies the properties of important biological molecules, like proteins. The biochemistry of cell metabolism and the system has been extensively described. Other areas of biochemistry include the code, protein synthesis, cell membrane transport. It began in the ancient Indian culture also with an interest in medicine and they also delved into the interest of bodies being composed of tissues. On the side of chemistry, early advancements were heavily attributed to exploration of interests but also included, metallurgy, the scientific method. In more recent times, the study of chemistry was marked by such as the development of Mendeleevs periodic table, Daltons atomic model. This last mention has the most importance of the three due to the fact that this law intertwines chemistry with thermodynamics in an intercalated manner. As early as the late 18th century and early 19th century, the digestion of meat by stomach secretions, however, the mechanism by which this occurred had not been identified. He wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment used to refer to chemical activity produced by living organisms. In 1897 Eduard Buchner began to study the ability of yeast extracts to ferment sugar despite the absence of living yeast cells. In a series of experiments at the University of Berlin, he found that the sugar was fermented even when there were no living yeast cells in the mixture and he named the enzyme that brought about the fermentation of sucrose zymase. In 1907 he received the Nobel Prize in Chemistry for his biochemical research, following Buchners example, enzymes are usually named according to the reaction they carry out. Typically the suffix -ase is added to the name of the substrate or the type of reaction, having shown that enzymes could function outside a living cell, the next step was to determine their biochemical nature. Sumner showed that the enzyme urease was a protein and crystallized it
5.
Cell biology
–
Cell biology is a branch of biology that studies the different structures and functions of the cell and focuses mainly on the idea of the cell as the basic unit of life. This is done both on a microscopic and molecular level as it encompasses prokaryotic cells and eukaryotic cells, knowing the components of cells and how cells work is fundamental to all biological sciences, it is also essential for research in bio-medical fields such as cancer, and other diseases. Research in cell biology is closely related to genetics, biochemistry, molecular biology, immunology, and developmental biology. The study of the cell is done on a level, however, most of the processes within the cell are made up of a mixture of small organic molecules, inorganic ions, hormones. Approximately 75-85% of the volume is due to water making it an indispensable solvent as a result of its polarity. These molecules within the cell, which operate as substrates, provide an environment for the cell to carry out metabolic reactions. The cell shape varies among the different types of organisms, and are then classified into two categories, eukaryotes and prokaryotes. Cell biology focuses more on the study of cells, and their signalling pathways. This environment of the cell is made up of hydrophilic and hydrophobic regions which allows for the exchange of the above-mentioned molecules and ions. The hydrophilic regions of the cell are mainly on the inside and outside of the cell, the cell membrane consists of lipids and proteins which accounts for its hydrophobicity as a result of being non-polar substances. Therefore, in order for these molecules to participate in reactions, within the cell and they accomplish this process of gaining access to the cell via, osmotic pressure, diffusion, concentration gradients, and membrane channels. Inside of the cell are extensive internal sub-cellular membrane-bounded compartments called organelles, cytoplasm - contents of the main fluid-filled space inside cells, chemical reactions also happen in this jelly-like substance. Nuclear Architecture is important for dictating nuclear function, vacuole - contain cell sap or other storage material. Vesicle - small membrane-bounded spheres inside cells which transport substances, the growth process of the cell does not refer to the size of the cell, but instead the density of the number of cells present in the organism at a given time. Cell growth pertains to the increase in the number of cells present in an organism as it grows and develops, Cells are the foundation of all organisms, they are the fundamental unit of life. The growth and development of the cell are essential for the maintenance of the host, for this process the cell goes through the steps of the cell cycle and development which involves cell growth, DNA replication, cell division, regeneration, specialization, and cell death. The cell cycle is divided into four phases, G1, S, G2. The G phases – which is the growth phase - makes up approximately 95% of the cycle
6.
Bioinformatics
–
Bioinformatics /ˌbaɪ. oʊˌɪnfərˈmætɪks/ is an interdisciplinary field that develops methods and software tools for understanding biological data. As an interdisciplinary field of science, bioinformatics combines computer science, statistics, mathematics, Bioinformatics has been used for in silico analyses of biological queries using mathematical and statistical techniques. Common uses of bioinformatics include the identification of genes and nucleotides. Often, such identification is made with the aim of understanding the genetic basis of disease, unique adaptations, desirable properties. In a less formal way, bioinformatics also tries to understand the principles within nucleic acid and protein sequences. Bioinformatics has become an important part of areas of biology. In experimental molecular biology, bioinformatics techniques such as image and signal processing allow extraction of useful results from large amounts of raw data, in the field of genetics and genomics, it aids in sequencing and annotating genomes and their observed mutations. It plays a role in the mining of biological literature. It also plays a role in the analysis of gene and protein expression and regulation, Bioinformatics tools aid in the comparison of genetic and genomic data and more generally in the understanding of evolutionary aspects of molecular biology. At a more level, it helps analyze and catalogue the biological pathways. In structural biology, it aids in the simulation and modeling of DNA, RNA, historically, the term bioinformatics did not mean what it means today. Paulien Hogeweg and Ben Hesper coined it in 1970 to refer to the study of processes in biotic systems. This definition placed bioinformatics as a parallel to biophysics or biochemistry. Computers became essential in molecular biology when protein sequences became available after Frederick Sanger determined the sequence of insulin in the early 1950s, comparing multiple sequences manually turned out to be impractical. A pioneer in the field was Margaret Oakley Dayhoff, who has been hailed by David Lipman, director of the National Center for Biotechnology Information, Dayhoff compiled one of the first protein sequence databases, initially published as books and pioneered methods of sequence alignment and molecular evolution. To study how normal cellular activities are altered in different disease states, therefore, the field of bioinformatics has evolved such that the most pressing task now involves the analysis and interpretation of various types of data. This includes nucleotide and amino acid sequences, protein domains, the actual process of analyzing and interpreting data is referred to as computational biology. For example, there are methods to locate a gene within a sequence, to predict protein structure and/or function, the primary goal of bioinformatics is to increase the understanding of biological processes
7.
Enzyme
–
Enzymes /ˈɛnzaɪmz/ are macromolecular biological catalysts. Enzymes accelerate, or catalyze, chemical reactions, the molecules at the beginning of the process upon which enzymes may act are called substrates and the enzyme converts these into different molecules, called products. Almost all metabolic processes in the cell need enzymes in order to occur at rates fast enough to sustain life, the set of enzymes made in a cell determines which metabolic pathways occur in that cell. The study of enzymes is called enzymology, enzymes are known to catalyze more than 5,000 biochemical reaction types. Most enzymes are proteins, although a few are catalytic RNA molecules, enzymes specificity comes from their unique three-dimensional structures. Like all catalysts, enzymes increase the rate of a reaction by lowering its activation energy, some enzymes can make their conversion of substrate to product occur many millions of times faster. An extreme example is orotidine 5-phosphate decarboxylase, which allows a reaction that would take millions of years to occur in milliseconds. Chemically, enzymes are like any catalyst and are not consumed in chemical reactions, enzymes differ from most other catalysts by being much more specific. Enzyme activity can be affected by other molecules, inhibitors are molecules that decrease enzyme activity, many drugs and poisons are enzyme inhibitors. An enzymes activity decreases markedly outside its optimal temperature and pH, some enzymes are used commercially, for example, in the synthesis of antibiotics. French chemist Anselme Payen was the first to discover an enzyme, diastase and he wrote that alcoholic fermentation is an act correlated with the life and organization of the yeast cells, not with the death or putrefaction of the cells. In 1877, German physiologist Wilhelm Kühne first used the term enzyme, the word enzyme was used later to refer to nonliving substances such as pepsin, and the word ferment was used to refer to chemical activity produced by living organisms. Eduard Buchner submitted his first paper on the study of yeast extracts in 1897, in a series of experiments at the University of Berlin, he found that sugar was fermented by yeast extracts even when there were no living yeast cells in the mixture. He named the enzyme that brought about the fermentation of sucrose zymase, in 1907, he received the Nobel Prize in Chemistry for his discovery of cell-free fermentation. Following Buchners example, enzymes are usually named according to the reaction they carry out, the biochemical identity of enzymes was still unknown in the early 1900s. Sumner showed that the enzyme urease was a protein and crystallized it. These three scientists were awarded the 1946 Nobel Prize in Chemistry, the discovery that enzymes could be crystallized eventually allowed their structures to be solved by x-ray crystallography. This high-resolution structure of lysozyme marked the beginning of the field of structural biology, an enzymes name is often derived from its substrate or the chemical reaction it catalyzes, with the word ending in -ase
8.
Genetics
–
Genetics is the study of genes, genetic variation, and heredity in living organisms. It is generally considered a field of biology, but intersects frequently with other life sciences and is strongly linked with the study of information systems. The father of genetics is Gregor Mendel, a late 19th-century scientist, Mendel studied trait inheritance, patterns in the way traits are handed down from parents to offspring. He observed that organisms inherit traits by way of discrete units of inheritance and this term, still used today, is a somewhat ambiguous definition of what is referred to as a gene. Gene structure and function, variation, and distribution are studied within the context of the cell, the organism, genetics has given rise to a number of subfields, including epigenetics and population genetics. Organisms studied within the broad field span the domain of life, including bacteria, plants, animals, genetic processes work in combination with an organisms environment and experiences to influence development and behavior, often referred to as nature versus nurture. The intracellular or extracellular environment of a cell or organism may switch gene transcription on or off, a classic example is two seeds of genetically identical corn, one placed in a temperate climate and one in an arid climate. The word genetics stems from the ancient Greek γενετικός genetikos meaning genitive/generative, the observation that living things inherit traits from their parents has been used since prehistoric times to improve crop plants and animals through selective breeding. The modern science of genetics, seeking to understand this process, prior to Mendel, Imre Festetics, a Hungarian noble, who lived in Kőszeg before Mendel, was the first who used the word genetics. He described several rules of inheritance in his work The genetic law of the Nature. His second law is the same as what Mendel published, in his third law, he developed the basic principles of mutation. Other theories of inheritance preceded his work, a popular theory during Mendels time was the concept of blending inheritance, the idea that individuals inherit a smooth blend of traits from their parents. Mendels work provided examples where traits were not blended after hybridization. Blending of traits in the progeny is now explained by the action of genes with quantitative effects. Another theory that had some support at that time was the inheritance of acquired characteristics, other theories included the pangenesis of Charles Darwin and Francis Galtons reformulation of pangenesis as both particulate and inherited. Modern genetics started with Gregor Johann Mendel, a scientist and Augustinian friar who studied the nature of inheritance in plants, the importance of Mendels work did not gain wide understanding until the 1890s, after his death, when other scientists working on similar problems re-discovered his research. William Bateson, a proponent of Mendels work, coined the word genetics in 1905, Bateson popularized the usage of the word genetics to describe the study of inheritance in his inaugural address to the Third International Conference on Plant Hybridization in London in 1906. After the rediscovery of Mendels work, scientists tried to determine which molecules in the cell were responsible for inheritance, in 1911, Thomas Hunt Morgan argued that genes are on chromosomes, based on observations of a sex-linked white eye mutation in fruit flies
9.
Immunology
–
Immunology is a branch of biology that covers the study of immune systems in all organisms. It was the Russian biologist Ilya Ilyich Mechnikov who boosted studies on immunology and he jabbed the thorn of a rose on a starfish and noted that,24 hours later, cells were surrounding the tip. It was a response of the body, trying to maintain its integrity. It was Mechnikov who first observed the phenomenon of phagocytosis, in which the body defends itself against a foreign body, Immunology has applications in numerous disciplines of medicine, particularly in the fields of organ transplantation, oncology, virology, bacteriology, parasitology, psychiatry, and dermatology. The important lymphoid organs of the system are the thymus and bone marrow, and chief lymphatic tissues such as spleen, tonsils, lymph vessels, lymph nodes, adenoids. Classical immunology ties in with the fields of epidemiology and medicine and it studies the relationship between the body systems, pathogens, and immunity. The earliest written mention of immunity can be traced back to the plague of Athens in 430 BCE, thucydides noted that people who had recovered from a previous bout of the disease could nurse the sick without contracting the illness a second time. Many other ancient societies have references to this phenomenon, but it was not until the 19th and 20th centuries before the concept developed into scientific theory. The study of the molecular and cellular components that comprise the immune system, the immune system has been divided into a more primitive innate immune system and, in vertebrates, an acquired or adaptive immune system. The latter is divided into humoral and cell-mediated components. The humoral response is defined as the interaction between antibodies and antigens, antibodies are specific proteins released from a certain class of immune cells known as B lymphocytes, while antigens are defined as anything that elicits the generation of antibodies. Immunology rests on an understanding of the properties of two biological entities and the cellular response to both. Immunological research continues to more specialized, pursuing non-classical models of immunity and functions of cells, organs. Clinical immunology is the study of diseases caused by disorders of the immune system and it also involves diseases of other systems, where immune reactions play a part in the pathology and clinical features. Other immune system include various hypersensitivities that respond inappropriately to otherwise harmless compounds. Clinical immunologists also study ways to prevent the immune systems attempts to destroy allografts, the body’s capability to react to antigen depends on a persons age, antigen type, maternal factors and the area where the antigen is presented. Neonates are said to be in a state of physiological immunodeficiency, once born, a child’s immune system responds favorably to protein antigens while not as well to glycoproteins and polysaccharides. In fact, many of the infections acquired by neonates are caused by low virulence organisms like Staphylococcus, in neonates, opsonic activity and the ability to activate the complement cascade is very limited
10.
Molecular biology
–
Writing in Nature in 1961, William Astbury described molecular biology as. It is concerned particularly with the forms of biological molecules and is predominantly three-dimensional and structural—which does not mean, however and it must at the same time inquire into genesis and function. Researchers in molecular biology use specific techniques native to molecular biology but increasingly combine these techniques and ideas from genetics. There is not a line between these disciplines. Biochemists focus heavily on the role, function, and structure of biomolecules, the study of the chemistry behind biological processes and the synthesis of biologically active molecules are examples of biochemistry. Genetics is the study of the effect of differences on organisms. This can often be inferred by the absence of a normal component, the study of mutants – organisms which lack one or more functional components with respect to the so-called wild type or normal phenotype. Genetic interactions can often confound simple interpretations of such knockout studies, molecular biology is the study of molecular underpinnings of the processes of replication, transcription, translation, and cell function. This picture, however, is undergoing revision in light of emerging novel roles for RNA, much of molecular biology is quantitative, and recently much work has been done at its interface with computer science in bioinformatics and computational biology. In the early 2000s, the study of structure and function. There is also a tradition of studying biomolecules from the ground up in biophysics. One of the most basic techniques of molecular biology to study protein function is molecular cloning, in this technique, DNA coding for a protein of interest is cloned using PCR and/or restriction enzymes into a plasmid. A vector has 3 distinctive features, an origin of replication, a multiple cloning site, the origin of replication will have promoter regions upstream from the replication/transcription start site. This plasmid can be inserted into either bacterial or animal cells, introducing DNA into bacterial cells can be done by transformation via uptake of naked DNA, conjugation via cell-cell contact or by transduction via viral vector. Introducing DNA into eukaryotic cells, such as cells, by physical or chemical means is called transfection. Several different transfection techniques are available, such as calcium phosphate transfection, electroporation, microinjection, the plasmid may be integrated into the genome, resulting in a stable transfection, or may remain independent of the genome, called transient transfection. DNA coding for a protein of interest is now inside a cell, a variety of systems, such as inducible promoters and specific cell-signaling factors, are available to help express the protein of interest at high levels. Large quantities of a protein can then be extracted from the bacterial or eukaryotic cell, polymerase chain reaction is an extremely versatile technique for copying DNA
11.
Structural biology
–
This architecture, the tertiary structure of molecules, depends in a complicated way on the molecules basic composition, or primary structures. Biomolecules are too small to see in detail even with the most advanced light microscopes, the methods that structural biologists use to determine their structures generally involve measurements on vast numbers of identical molecules at the same time. But variations on these methods are used to watch nascent or denatured molecules assume or reassume their native states. A third approach that structural biologists take to understanding structure is bioinformatics to look for patterns among the sequences that give rise to particular shapes. Researchers often can deduce aspects of the structure of membrane proteins based on the membrane topology predicted by hydrophobicity analysis. In the past few years it has become possible for highly accurate physical models to complement the in silico study of biological structures. Examples of these models can be found in the Protein Data Bank
12.
Glossary of chemistry terms
–
This page is a glossary of chemistry terms. Chemistry has a vocabulary and a significant amount of jargon. This is a list of terms, including laboratory tools, glassware. Chemistry itself is a science concerned with the composition, structure. It represents 1 mol of electrons, or the Avogadro number of electrons,6.022 ×1023 electrons, ficks laws of diffusion - frequency – number of cycles per unit of time. 023X10^23 atoms group – the elements in a column of the periodic table. Jodium – Latin name of the element iodine Joule – The SI unit of energy. Kelvin – A unit of measure for temperature based upon an absolute scale, lanthanides – Elements 57 through 71 lattice – Unique arrangement of atoms or molecules in a crystalline liquid or solid. Laws of thermodynamics Lewis acid - Lewis base - liquid – A state of matter in which force is less than or equal to the separating force. Light – Portion of the spectrum which is visible to the naked eye. London dispersion forces – A weak intermolecular force laws of motion – An object in motion stays in motion, magnetic quantum number - manometer - Instrument to measure pressure, invented by Evangelista Torricelli in 1643. It is made up of solutes and solvents, but there are some positive and negative charges in it, due to the formal charge, owing to the partial charges of its constituent atoms
13.
Chemical process
–
In a scientific sense, a chemical process is a method or means of somehow changing one or more chemicals or chemical compounds. Such a chemical process can occur by itself or be caused by an outside force, neither of these definitions is exact in the sense that one can always tell definitively what is a chemical process and what is not, they are practical definitions. There is also significant overlap in these two definition variations, because of the inexactness of the definition, chemists and other scientists use the term chemical process only in a general sense or in the engineering sense. However, in the sense, the term chemical process is used extensively. The rest of the article will cover the type of chemical process. Although this type of process may sometimes involve only one step, often multiple steps. In a plant, each of the unit operations commonly occur in individual vessels or sections of the plant called units, often, one or more chemical reactions are involved, but other ways of changing chemical composition may be used, such as mixing or separation processes. The process steps may be sequential in time or sequential in space along a stream of flowing or moving material, see Chemical plant. For a given amount of a material or product material. These amounts can be scaled up or down to suit the desired capacity or operation of a chemical plant built for such a process. More than one plant may use the same chemical process. Chemical processes like distillation and crystallization go back to alchemy in Alexandria, such chemical processes can be illustrated generally as block flow diagrams or in more detail as process flow diagrams. Block flow diagrams show the units as blocks and the streams flowing between them as connecting lines with arrowheads to show direction of flow, unit processing is the basic processing in chemical engineering. Together with unit operations it forms the main principle of the chemical industries. Each genre of unit processing follows the same chemical law much as each genre of unit operations follows the physical law
14.
Organism
–
In biology, an organism is any contiguous living system, such as an animal, plant, fungus, protist, archaeon, or bacterium. All known types of organisms are capable of some degree of response to stimuli, reproduction, growth and development and homeostasis. An organism consists of one or more cells, when it has one cell it is known as an organism. Most unicellular organisms are of microscopic scale and are thus described as microorganisms. Humans are multicellular organisms composed of trillions of cells grouped into specialized tissues. An organism may be either a prokaryote or a eukaryote, prokaryotes are represented by two separate domains—bacteria and archaea. Eukaryotic organisms are characterized by the presence of a cell nucleus. Fungi, animals and plants are examples of kingdoms of organisms within the eukaryotes, estimates on the number of Earths current species range from 10 million to 14 million, of which only about 1.2 million have been documented. More than 99% of all species, amounting to five billion species. In 2016, a set of 355 genes from the last universal ancestor of all living organisms living was identified. The term organism first appeared in the English language in 1703 and it is directly related to the term organization. There is a tradition of defining organisms as self-organizing beings. An organism may be defined as an assembly of molecules functioning as a more or less stable whole that exhibits the properties of life. Dictionary definitions can be broad, using such as any living structure, such as a plant, animal, fungus or bacterium, capable of growth. Many definitions exclude viruses and possible man-made non-organic life forms, as viruses are dependent on the machinery of a host cell for reproduction. A superorganism is an organism consisting of individuals working together as a single functional or social unit. There has been controversy about the best way to define the organism, several contributions are responses to the suggestion that the category of organism may well not be adequate in biology. Viruses are not typically considered to be organisms because they are incapable of autonomous reproduction and this controversy is problematic because some cellular organisms are also incapable of independent survival and live as obligatory intracellular parasites
15.
Life
–
Various forms of life exist, such as plants, animals, fungi, protists, archaea, and bacteria. The criteria can at times be ambiguous and may or may not define viruses, viroids, biology is the primary science concerned with the study of life, although many other sciences are involved. The definition of life is controversial, the current definition is that organisms maintain homeostasis, are composed of cells, undergo metabolism, can grow, adapt to their environment, respond to stimuli, and reproduce. However, many other definitions have been proposed, and there are some borderline cases. Modern definitions are more complex, with input from a diversity of scientific disciplines, biophysicists have proposed many definitions based on chemical systems, there are also some living systems theories, such as the Gaia hypothesis, the idea that the Earth itself is alive. Another theory is that life is the property of systems, and yet another is elaborated in complex systems biology. Abiogenesis describes the process of life arising from non-living matter. Properties common to all organisms include the need for certain chemical elements to sustain biochemical functions. Life on Earth first appeared as early as 4.28 billion years ago, soon after ocean formation 4.41 billion years ago, Earths current life may have descended from an RNA world, although RNA-based life may not have been the first. The mechanism by which began on Earth is unknown, though many hypotheses have been formulated and are often based on the Miller–Urey experiment. The earliest known forms are microfossils of bacteria. In July 2016, scientists reported identifying a set of 355 genes believed to be present in the last universal ancestor of all living organisms. Since its primordial beginnings, life on Earth has changed its environment on a time scale. To survive in most ecosystems, life must often adapt to a range of conditions. Some microorganisms, called extremophiles, thrive in physically or geochemically extreme environments that are detrimental to most other life on Earth, Aristotle was the first person to classify organisms. Later, Carl Linnaeus introduced his system of nomenclature for the classification of species. Eventually new groups and categories of life were discovered, such as cells and microorganisms, cells are sometimes considered the smallest units and building blocks of life. There are two kinds of cells, prokaryotic and eukaryotic, both of which consist of cytoplasm enclosed within a membrane and contain many such as proteins
16.
Biology
–
Biology is a natural science concerned with the study of life and living organisms, including their structure, function, growth, evolution, distribution, identification and taxonomy. Modern biology is a vast and eclectic field, composed of branches and subdisciplines. However, despite the broad scope of biology, there are certain unifying concepts within it that consolidate it into single, coherent field. In general, biology recognizes the cell as the unit of life, genes as the basic unit of heredity. It is also understood today that all organisms survive by consuming and transforming energy and by regulating their internal environment to maintain a stable, the term biology is derived from the Greek word βίος, bios, life and the suffix -λογία, -logia, study of. The Latin-language form of the term first appeared in 1736 when Swedish scientist Carl Linnaeus used biologi in his Bibliotheca botanica, the first German use, Biologie, was in a 1771 translation of Linnaeus work. In 1797, Theodor Georg August Roose used the term in the preface of a book, karl Friedrich Burdach used the term in 1800 in a more restricted sense of the study of human beings from a morphological, physiological and psychological perspective. The science that concerns itself with these objects we will indicate by the biology or the doctrine of life. Although modern biology is a recent development, sciences related to. Natural philosophy was studied as early as the ancient civilizations of Mesopotamia, Egypt, the Indian subcontinent, however, the origins of modern biology and its approach to the study of nature are most often traced back to ancient Greece. While the formal study of medicine back to Hippocrates, it was Aristotle who contributed most extensively to the development of biology. Especially important are his History of Animals and other works where he showed naturalist leanings, and later more empirical works that focused on biological causation and the diversity of life. Aristotles successor at the Lyceum, Theophrastus, wrote a series of books on botany that survived as the most important contribution of antiquity to the plant sciences, even into the Middle Ages. Scholars of the medieval Islamic world who wrote on biology included al-Jahiz, Al-Dīnawarī, who wrote on botany, biology began to quickly develop and grow with Anton van Leeuwenhoeks dramatic improvement of the microscope. It was then that scholars discovered spermatozoa, bacteria, infusoria, investigations by Jan Swammerdam led to new interest in entomology and helped to develop the basic techniques of microscopic dissection and staining. Advances in microscopy also had a impact on biological thinking. In the early 19th century, a number of biologists pointed to the importance of the cell. Thanks to the work of Robert Remak and Rudolf Virchow, however, meanwhile, taxonomy and classification became the focus of natural historians
17.
Chemistry
–
Chemistry is a branch of physical science that studies the composition, structure, properties and change of matter. Chemistry is sometimes called the science because it bridges other natural sciences, including physics. For the differences between chemistry and physics see comparison of chemistry and physics, the history of chemistry can be traced to alchemy, which had been practiced for several millennia in various parts of the world. The word chemistry comes from alchemy, which referred to a set of practices that encompassed elements of chemistry, metallurgy, philosophy, astrology, astronomy, mysticism. An alchemist was called a chemist in popular speech, and later the suffix -ry was added to this to describe the art of the chemist as chemistry, the modern word alchemy in turn is derived from the Arabic word al-kīmīā. In origin, the term is borrowed from the Greek χημία or χημεία and this may have Egyptian origins since al-kīmīā is derived from the Greek χημία, which is in turn derived from the word Chemi or Kimi, which is the ancient name of Egypt in Egyptian. Alternately, al-kīmīā may derive from χημεία, meaning cast together, in retrospect, the definition of chemistry has changed over time, as new discoveries and theories add to the functionality of the science. The term chymistry, in the view of noted scientist Robert Boyle in 1661, in 1837, Jean-Baptiste Dumas considered the word chemistry to refer to the science concerned with the laws and effects of molecular forces. More recently, in 1998, Professor Raymond Chang broadened the definition of chemistry to mean the study of matter, early civilizations, such as the Egyptians Babylonians, Indians amassed practical knowledge concerning the arts of metallurgy, pottery and dyes, but didnt develop a systematic theory. Greek atomism dates back to 440 BC, arising in works by such as Democritus and Epicurus. In 50 BC, the Roman philosopher Lucretius expanded upon the theory in his book De rerum natura, unlike modern concepts of science, Greek atomism was purely philosophical in nature, with little concern for empirical observations and no concern for chemical experiments. Work, particularly the development of distillation, continued in the early Byzantine period with the most famous practitioner being the 4th century Greek-Egyptian Zosimos of Panopolis. He formulated Boyles law, rejected the four elements and proposed a mechanistic alternative of atoms. Before his work, though, many important discoveries had been made, the Scottish chemist Joseph Black and the Dutchman J. B. English scientist John Dalton proposed the theory of atoms, that all substances are composed of indivisible atoms of matter. Davy discovered nine new elements including the alkali metals by extracting them from their oxides with electric current, british William Prout first proposed ordering all the elements by their atomic weight as all atoms had a weight that was an exact multiple of the atomic weight of hydrogen. The inert gases, later called the noble gases were discovered by William Ramsay in collaboration with Lord Rayleigh at the end of the century, thereby filling in the basic structure of the table. Organic chemistry was developed by Justus von Liebig and others, following Friedrich Wöhlers synthesis of urea which proved that organisms were, in theory
18.
Protein
–
Proteins are large biomolecules, or macromolecules, consisting of one or more long chains of amino acid residues. Proteins perform a vast array of functions within organisms, including catalysing metabolic reactions, DNA replication, responding to stimuli, a linear chain of amino acid residues is called a polypeptide. A protein contains at least one long polypeptide, short polypeptides, containing less than 20–30 residues, are rarely considered to be proteins and are commonly called peptides, or sometimes oligopeptides. The individual amino acid residues are bonded together by peptide bonds, the sequence of amino acid residues in a protein is defined by the sequence of a gene, which is encoded in the genetic code. In general, the code specifies 20 standard amino acids, however. Sometimes proteins have non-peptide groups attached, which can be called prosthetic groups or cofactors, proteins can also work together to achieve a particular function, and they often associate to form stable protein complexes. Once formed, proteins only exist for a period of time and are then degraded and recycled by the cells machinery through the process of protein turnover. A proteins lifespan is measured in terms of its half-life and covers a wide range and they can exist for minutes or years with an average lifespan of 1–2 days in mammalian cells. Abnormal and or misfolded proteins are degraded more rapidly due to being targeted for destruction or due to being unstable. Like other biological macromolecules such as polysaccharides and nucleic acids, proteins are essential parts of organisms, many proteins are enzymes that catalyse biochemical reactions and are vital to metabolism. Proteins also have structural or mechanical functions, such as actin and myosin in muscle and the proteins in the cytoskeleton, other proteins are important in cell signaling, immune responses, cell adhesion, and the cell cycle. In animals, proteins are needed in the diet to provide the essential amino acids that cannot be synthesized, digestion breaks the proteins down for use in the metabolism. Methods commonly used to study structure and function include immunohistochemistry, site-directed mutagenesis, X-ray crystallography, nuclear magnetic resonance. Most proteins consist of linear polymers built from series of up to 20 different L-α-amino acids, all proteinogenic amino acids possess common structural features, including an α-carbon to which an amino group, a carboxyl group, and a variable side chain are bonded. Only proline differs from this structure as it contains an unusual ring to the N-end amine group. The amino acids in a chain are linked by peptide bonds. Once linked in the chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen. The peptide bond has two forms that contribute some double-bond character and inhibit rotation around its axis, so that the alpha carbons are roughly coplanar
19.
Cell (biology)
–
The cell is the basic structural, functional, and biological unit of all known living organisms. A cell is the smallest unit of life that can replicate independently, the study of cells is called cell biology. Cells consist of cytoplasm enclosed within a membrane, which contains many such as proteins. Organisms can be classified as unicellular or multicellular, while the number of cells in plants and animals varies from species to species, humans contain more than 10 trillion cells. Most plant and animal cells are only under a microscope. The cell was discovered by Robert Hooke in 1665, who named the unit for its resemblance to cells inhabited by Christian monks in a monastery. Cells emerged on Earth at least 3.5 billion years ago, Cells are of two types, eukaryotic, which contain a nucleus, and prokaryotic, which do not. Prokaryotes are single-celled organisms, while eukaryotes can be either single-celled or multicellular, prokaryotic cells were the first form of life on Earth, characterised by having vital biological processes including cell signaling and being self-sustaining. They are simpler and smaller than eukaryotic cells, and lack membrane-bound organelles such as the nucleus, prokaryotes include two of the domains of life, bacteria and archaea. The DNA of a prokaryotic cell consists of a chromosome that is in direct contact with the cytoplasm. The nuclear region in the cytoplasm is called the nucleoid, most prokaryotes are the smallest of all organisms ranging from 0.5 to 2.0 µm in diameter. Though most prokaryotes have both a cell membrane and a wall, there are exceptions such as Mycoplasma and Thermoplasma which only possess the cell membrane layer. The envelope gives rigidity to the cell and separates the interior of the cell from its environment, the cell wall consists of peptidoglycan in bacteria, and acts as an additional barrier against exterior forces. It also prevents the cell from expanding and bursting from osmotic pressure due to a hypotonic environment, some eukaryotic cells also have a cell wall. Inside the cell is the region that contains the genome, ribosomes. The genetic material is found in the cytoplasm. Prokaryotes can carry extrachromosomal DNA elements called plasmids, which are usually circular, linear bacterial plasmids have been identified in several species of spirochete bacteria, including members of the genus Borrelia notably Borrelia burgdorferi, which causes Lyme disease. Though not forming a nucleus, the DNA is condensed in a nucleoid, plasmids encode additional genes, such as antibiotic resistance genes
20.
Tissue (biology)
–
In biology, tissue is a cellular organizational level intermediate between cells and a complete organ. A tissue is an ensemble of similar cells from the origin that together carry out a specific function. Organs are then formed by the grouping together of multiple tissues. The study of tissue is known as histology or, in connection with disease, the classical tools for studying tissues are the paraffin block in which tissue is embedded and then sectioned, the histological stain, and the optical microscope. In the last couple of decades, developments in microscopy, immunofluorescence. With these tools, the appearances of tissues can be examined in health and disease. Animal tissues are grouped into four types, connective, muscle, nervous. Collections of tissues joined in structural units to serve a common function compose organs, while all animals can generally be considered to contain the four tissue types, the manifestation of these tissues can differ depending on the type of organism. For example, the origin of the cells comprising a particular type may differ developmentally for different classifications of animals. By contrast, a true epithelial tissue is present only in a layer of cells held together via occluding junctions called tight junctions. This tissue covers all surfaces that come in contact with the external environment such as the skin, the airways. It serves functions of protection, secretion, and absorption, and is separated from other tissues below by a basal lamina and they are made up of cells separated by non-living material, which is called an extracellular matrix. This matrix can be liquid or rigid, for example, blood contains plasma as its matrix and bones matrix is rigid. Connective tissue gives shape to organs and holds them in place, blood, bone, tendon, ligament, adipose and areolar tissues are examples of connective tissues. One method of classifying tissues is to divide them into three types, fibrous connective tissue, skeletal connective tissue, and fluid connective tissue. Muscle cells form the active contractile tissue of the known as muscle tissue or muscular tissue. Muscle tissue functions to force and cause motion, either locomotion or movement within internal organs. Cells comprising the nervous system and peripheral nervous system are classified as nervous tissue
21.
Organ (anatomy)
–
In biology, an organ or viscus is a collection of tissues joined in a structural unit to serve a common function. In anatomy, a viscus is an organ, and viscera is the plural form. Organs are composed of main tissue, parenchyma, and sporadic tissues, the main tissue is that which is unique for the specific organ, such as the myocardium, the main tissue of the heart, while sporadic tissues include the nerves, blood vessels, and connective tissues. The main tissues that make up an organ tend to have common embryologic origins, functionally related organs often cooperate to form whole organ systems. Organs exist in all biological organisms, in particular they are not restricted to animals. In single-cell organisms like bacteria, the analogue of an organ is called organelle. A hollow organ is an organ that forms a hollow tube or pouch, such as the stomach or intestine, or that includes a cavity. Two or more organs working together in the execution of a specific body function form an organ system, the functions of organ systems often share significant overlap. For instance, the nervous and endocrine system both operate via an organ, the hypothalamus. For this reason, the two systems are combined and studied as the neuroendocrine system, the same is true for the musculoskeletal system because of the relationship between the muscular and skeletal systems. Mammals such as humans have a variety of organ systems and these specific systems are also widely studied in human anatomy. Cardiovascular system, pumping and channeling blood to and from the body and lungs with heart, digestive system, digestion and processing food with salivary glands, esophagus, stomach, liver, gallbladder, pancreas, intestines, colon, rectum and anus. Excretory system, kidneys, ureters, bladder and urethra involved in balance, electrolyte balance. Integumentary system, skin, hair and nails, nervous system, collecting, transferring and processing information with brain, spinal cord and nerves. Reproductive system, the sex organs, such as ovaries, fallopian tubes, uterus, vulva, vagina, testes, vas deferens, seminal vesicles, prostate, respiratory system, the organs used for breathing, the pharynx, larynx, trachea, bronchi, lungs and diaphragm. Skeletal system, structural support and protection with bones, cartilage, ligaments, the organ level of organisation in animals can be first detected in flatworms and the more advanced phyla. The less-advanced taxa do not show consolidation of their tissues into organs, the study of plant organs is referred to as plant morphology, rather than anatomy, as in animal systems. Organs of plants can be divided into vegetative and reproductive, vegetative plant organs are roots, stems, and leaves
22.
Molecule
–
A molecule is an electrically neutral group of two or more atoms held together by chemical bonds. Molecules are distinguished from ions by their lack of electrical charge, however, in quantum physics, organic chemistry, and biochemistry, the term molecule is often used less strictly, also being applied to polyatomic ions. In the kinetic theory of gases, the molecule is often used for any gaseous particle regardless of its composition. According to this definition, noble gas atoms are considered molecules as they are in fact monoatomic molecules. A molecule may be homonuclear, that is, it consists of atoms of one element, as with oxygen, or it may be heteronuclear. Atoms and complexes connected by non-covalent interactions, such as hydrogen bonds or ionic bonds, are not considered single molecules. Molecules as components of matter are common in organic substances and they also make up most of the oceans and atmosphere. Also, no typical molecule can be defined for ionic crystals and covalent crystals, the theme of repeated unit-cellular-structure also holds for most condensed phases with metallic bonding, which means that solid metals are also not made of molecules. In glasses, atoms may also be together by chemical bonds with no presence of any definable molecule. The science of molecules is called molecular chemistry or molecular physics, in practice, however, this distinction is vague. In molecular sciences, a molecule consists of a system composed of two or more atoms. Polyatomic ions may sometimes be thought of as electrically charged molecules. The term unstable molecule is used for very reactive species, i. e, according to Merriam-Webster and the Online Etymology Dictionary, the word molecule derives from the Latin moles or small unit of mass. Molecule – extremely minute particle, from French molécule, from New Latin molecula, diminutive of Latin moles mass, a vague meaning at first, the vogue for the word can be traced to the philosophy of Descartes. The definition of the molecule has evolved as knowledge of the structure of molecules has increased, earlier definitions were less precise, defining molecules as the smallest particles of pure chemical substances that still retain their composition and chemical properties. Molecules are held together by covalent bonding or ionic bonding. Several types of non-metal elements exist only as molecules in the environment, for example, hydrogen only exists as hydrogen molecule. A molecule of a compound is made out of two or more elements, a covalent bond is a chemical bond that involves the sharing of electron pairs between atoms
23.
Genetic code
–
The genetic code is the set of rules by which information encoded within genetic material is translated into proteins by living cells. Translation is accomplished by the ribosome, which links amino acids in an order specified by mRNA, using transfer RNA molecules to carry amino acids, the genetic code is highly similar among all organisms and can be expressed in a simple table with 64 entries. The code defines how sequences of nucleotide triplets, called codons, with some exceptions, a three-nucleotide codon in a nucleic acid sequence specifies a single amino acid. The vast majority of genes are encoded with a single scheme and that scheme is often referred to as the canonical or standard genetic code, or simply the genetic code, though variant codes exist. While the genetic code determines a proteins amino acid sequence, other genomic regions determine when, efforts to understand how proteins are encoded began after DNAs structure was discovered in 1953. George Gamow postulated that sets of three bases must be employed to encode the 20 standard amino acids used by living cells to build proteins, the Crick, Brenner et al. experiment first demonstrated that codons consist of three DNA bases. Marshall Nirenberg and Heinrich J. Matthaei were the first to reveal the nature of a codon in 1961 and they used a cell-free system to translate a poly-uracil RNA sequence and discovered that the polypeptide that they had synthesized consisted of only the amino acid phenylalanine. They thereby deduced that the codon UUU specified the amino acid phenylalanine, therefore, the codon AAA specified the amino acid lysine, and the codon CCC specified the amino acid proline. Using various copolymers most of the remaining codons were then determined, subsequent work by Har Gobind Khorana identified the rest of the genetic code. Shortly thereafter, Robert W. Holley determined the structure of transfer RNA and this work was based upon Ochoas earlier studies, yielding the latter the Nobel Prize in Physiology or Medicine in 1959 for work on the enzymology of RNA synthesis. Extending this work, Nirenberg and Philip Leder revealed the triplet nature. In these experiments, various combinations of mRNA were passed through a filter that contained ribosomes, unique triplets promoted the binding of specific tRNAs to the ribosome. Leder and Nirenberg were able to determine the sequences of 54 out of 64 codons in their experiments, Khorana, Holley and Nirenberg received the 1968 Nobel for their work. The three stop codons were named by discoverers Richard Epstein and Charles Steinberg, amber was named after their friend Harris Bernstein, whose last name means amber in German. The other two stop codons were named ochre and opal in order to keep the color names theme, H. Murakami and M. Sisido extended some codons to have four and five bases. Steven A. Benner constructed a functional 65th codon, in 2016 the first stable semisynthetic organism was created. It was a bacterium with two synthetic bases, in 2017 a mouse engineered with an extended genetic code that can produce proteins with unnatural amino acids was reported. A codon is defined by the initial nucleotide from which starts and sets the frame for a run of successive triplets
24.
DNA
–
Deoxyribonucleic acid is a molecule that carries the genetic instructions used in the growth, development, functioning and reproduction of all known living organisms and many viruses. DNA and RNA are nucleic acids, alongside proteins, lipids and complex carbohydrates, most DNA molecules consist of two biopolymer strands coiled around each other to form a double helix. The two DNA strands are termed polynucleotides since they are composed of simpler units called nucleotides. Each nucleotide is composed of one of four nitrogen-containing nucleobases—cytosine, guanine, adenine, or thymine —a sugar called deoxyribose, and a phosphate group. The nucleotides are joined to one another in a chain by covalent bonds between the sugar of one nucleotide and the phosphate of the next, resulting in an alternating sugar-phosphate backbone. The nitrogenous bases of the two polynucleotide strands are bound together, according to base pairing rules, with hydrogen bonds to make double-stranded DNA. The total amount of related DNA base pairs on Earth is estimated at 5.0 x 1037, in comparison the total mass of the biosphere has been estimated to be as much as 4 trillion tons of carbon. The DNA backbone is resistant to cleavage, and both strands of the double-stranded structure store the same biological information and this information is replicated as and when the two strands separate. A large part of DNA is non-coding, meaning that these sections do not serve as patterns for protein sequences, the two strands of DNA run in opposite directions to each other and are thus antiparallel. Attached to each sugar is one of four types of nucleobases and it is the sequence of these four nucleobases along the backbone that encodes biological information. RNA strands are created using DNA strands as a template in a process called transcription, under the genetic code, these RNA strands are translated to specify the sequence of amino acids within proteins in a process called translation. Within eukaryotic cells DNA is organized into structures called chromosomes. During cell division these chromosomes are duplicated in the process of DNA replication, eukaryotic organisms store most of their DNA inside the cell nucleus and some of their DNA in organelles, such as mitochondria or chloroplasts. In contrast prokaryotes store their DNA only in the cytoplasm, within the eukaryotic chromosomes, chromatin proteins such as histones compact and organize DNA. These compact structures guide the interactions between DNA and other proteins, helping control which parts of the DNA are transcribed, DNA was first isolated by Friedrich Miescher in 1869. DNA is used by researchers as a tool to explore physical laws and theories, such as the ergodic theorem. The unique material properties of DNA have made it an attractive molecule for material scientists and engineers interested in micro-, among notable advances in this field are DNA origami and DNA-based hybrid materials. DNA is a polymer made from repeating units called nucleotides
25.
Macromolecule
–
A macromolecule is a very large molecule, such as protein, commonly created by polymerization of smaller subunits. They are typically composed of thousands of atoms or more, the most common macromolecules in biochemistry are biopolymers and large non-polymeric molecules. Synthetic macromolecules include common plastics and synthetic fibres as well as materials such as carbon nanotubes. The term macromolecule was coined by Nobel laureate Hermann Staudinger in the 1920s, usage of the term to describe large molecules varies among the disciplines. According to the standard IUPAC definition, the term macromolecule as used in science refers only to a single molecule. For example, a polymeric molecule is appropriately described as a macromolecule or polymer molecule rather than a polymer. Because of their size, macromolecules are not conveniently described in terms of stoichiometry alone, the structure of simple macromolecules, such as homopolymers, may be described in terms of the individual monomer subunit and total molecular mass. Complicated biomacromolecules, on the hand, require multi-faceted structural description such as the hierarchy of structures used to describe proteins. In British English. Macromolecules often have physical properties that do not occur for smaller molecules. For example, DNA in a solution can be simply by sucking the solution through an ordinary straw because the physical forces on the molecule can overcome the strength of its covalent bonds. The 1964 edition of Linus Paulings College Chemistry asserted that DNA in nature is never longer than about 5,000 base pairs and this error arose because biochemists were inadvertently breaking their samples into fragments. In fact, the DNA of chromosomes can be hundreds of millions of base pairs long, another common macromolecular property that does not characterize smaller molecules is their relative insolubility in water and similar solvents, instead forming colloids. Many require salts or particular ions to dissolve in water, similarly, many proteins will denature if the solute concentration of their solution is too high or too low. High concentrations of macromolecules in a solution can alter the rates and equilibrium constants of the reactions of other macromolecules and this comes from macromolecules excluding other molecules from a large part of the volume of the solution, thereby increasing the effective concentrations of these molecules. All living organisms are dependent on three essential biopolymers for their functions, DNA, RNA and Proteins. Each of these molecules is required for life since each plays a distinct, the simple summary is that DNA makes RNA, and then RNA makes proteins. DNA, RNA and proteins all consist of a structure of related building blocks. In general, they are all unbranched polymers, and so can be represented in the form of a string
26.
Nucleic acid
–
Nucleic acids are biopolymers, or large biomolecules, essential to all known forms of life. They are composed of monomers, which are made of three components, a 5-carbon sugar, a phosphate group, and a nitrogenous base. If the sugar is a simple ribose, the polymer is RNA, if the sugar is derived from ribose as deoxyribose, Nucleic acids are arguably the most important of all biomolecules. They are found in abundance in all living things, where they function to create and encode, the encoded information is contained and conveyed via the nucleic acid sequence, which provides the ladder-step ordering of nucleotides within the molecules of RNA and DNA. Using amino acids and the known as protein synthesis, the specific sequencing in DNA of these nucleobase-pairs enables storing and transmitting coded instructions as genes. In RNA, base-pair sequencing provides for manufacturing new proteins that determine the frames and parts, Nucleic acids were discovered by Friedrich Miescher in 1869. In 1889 Richard Altmann discovered that nuclein has acidic properties, and it became called nucleic acid In 1938 Astbury, in 1953 Watson and Crick determined the structure of DNA. The term nucleic acid is the name for DNA and RNA, members of a family of biopolymers. Nucleic acids were named for their initial discovery within the nucleus, all living cells contain both DNA and RNA, while viruses contain either DNA or RNA, but usually not both. The basic component of nucleic acids is the nucleotide, each of which contains a pentose sugar, a phosphate group. Nucleic acids are generated within the laboratory, through the use of enzymes. The chemical methods also enable the generation of altered nucleic acids that are not found in nature, Nucleic acids are generally very large molecules. Indeed, DNA molecules are probably the largest individual molecules known, well-studied biological nucleic acid molecules range in size from 21 nucleotides to large chromosomes. In most cases, naturally occurring DNA molecules are double-stranded and RNA molecules are single-stranded, Nucleic acids are linear polymers of nucleotides. Each nucleotide consists of three components, a purine or pyrimidine nucleobase, a sugar, and a phosphate group. The substructure consisting of a nucleobase plus sugar is termed a nucleoside, Nucleic acid types differ in the structure of the sugar in their nucleotides–DNA contains 2-deoxyribose while RNA contains ribose. Also, the found in the two nucleic acid types are different, adenine, cytosine, and guanine are found in both RNA and DNA, while thymine occurs in DNA and uracil occurs in RNA. The sugars and phosphates in nucleic acids are connected to other in an alternating chain through phosphodiester linkages
27.
Carbohydrate
–
A carbohydrate is a biological molecule consisting of carbon, hydrogen and oxygen atoms, usually with a hydrogen–oxygen atom ratio of 2,1, in other words, with the empirical formula Cmn. This formula holds true for monosaccharides, some exceptions exist, for example, deoxyribose, a sugar component of DNA, has the empirical formula C5H10O4. Carbohydrates are technically hydrates of carbon, structurally it is accurate to view them as polyhydroxy aldehydes and ketones. The term is most common in biochemistry, where it is a synonym of saccharide, a group that includes sugars, starch, the saccharides are divided into four chemical groups, monosaccharides, disaccharides, oligosaccharides, and polysaccharides. Monosaccharides and disaccharides, the smallest carbohydrates, are referred to as sugars. The word saccharide comes from the Greek word σάκχαρον, meaning sugar, while the scientific nomenclature of carbohydrates is complex, the names of the monosaccharides and disaccharides very often end in the suffix -ose. For example, grape sugar is the glucose, cane sugar is the disaccharide sucrose. Carbohydrates perform numerous roles in living organisms, polysaccharides serve for the storage of energy and as structural components. The 5-carbon monosaccharide ribose is an important component of coenzymes and the backbone of the genetic molecule known as RNA, the related deoxyribose is a component of DNA. Saccharides and their derivatives include many other important biomolecules that play key roles in the system, fertilization, preventing pathogenesis, blood clotting. In food science and in informal contexts, the term carbohydrate often means any food that is particularly rich in the complex carbohydrate starch or simple carbohydrates. Often in lists of information, such as the USDA National Nutrient Database, the term carbohydrate is used for everything other than water, protein, fat, ash. This will include chemical compounds such as acetic or lactic acid, carbohydrates are found in wide variety of foods. The important sources are cereals, potatoes, sugarcane, fruits, table sugar, bread, milk, starch and sugar are the important carbohydrates in our diet. Starch is abundant in potatoes, maize, rice and other cereals, sugar appears in our diet mainly as sucrose which is added to drinks and many prepared foods such as jam, biscuits and cakes. Glucose and fructose are found naturally in fruits and some vegetables. Glycogen is carbohydrate found in the liver and muscles, cellulose in the cell wall of all plant tissue is a carbohydrate. It is important in our diet as fibre which helps to maintain a healthy digestive system, formerly the name carbohydrate was used in chemistry for any compound with the formula Cm n
28.
Lipid
–
In biology, lipids comprise a group of naturally occurring molecules that include fats, waxes, sterols, fat-soluble vitamins, monoglycerides, diglycerides, triglycerides, phospholipids, and others. The main biological functions of lipids include storing energy, signaling, lipids have applications in the cosmetic and food industries as well as in nanotechnology. Biological lipids originate entirely or in part from two types of biochemical subunits or building-blocks, ketoacyl and isoprene groups. Although the term lipid is sometimes used as a synonym for fats, fats are a subgroup of lipids called triglycerides, lipids also encompass molecules such as fatty acids and their derivatives, as well as other sterol-containing metabolites such as cholesterol. Although humans and other mammals use various biosynthetic pathways both to break down and to synthesize lipids, some essential lipids cannot be made this way, the word lipid stems etymologically from the Greek lipos. The fatty acid structure is one of the most fundamental categories of biological lipids, the carbon chain, typically between four and 24 carbons long, may be saturated or unsaturated, and may be attached to functional groups containing oxygen, halogens, nitrogen, and sulfur. If a fatty acid contains a double bond, there is the possibility of either a cis or trans geometric isomerism, cis-double bonds cause the fatty acid chain to bend, an effect that is compounded with more double bonds in the chain. This in turn plays an important role in the structure and function of cell membranes, most naturally occurring fatty acids are of the cis configuration, although the trans form does exist in some natural and partially hydrogenated fats and oils. Examples of biologically important fatty acids include the eicosanoids, derived primarily from arachidonic acid and eicosapentaenoic acid, that include prostaglandins, leukotrienes, docosahexaenoic acid is also important in biological systems, particularly with respect to sight. Other major lipid classes in the fatty acid category are the fatty esters, fatty esters include important biochemical intermediates such as wax esters, fatty acid thioester coenzyme A derivatives, fatty acid thioester ACP derivatives and fatty acid carnitines. The fatty amides include N-acyl ethanolamines, such as the cannabinoid neurotransmitter anandamide, glycerolipids are composed of mono-, di-, and tri-substituted glycerols, the best-known being the fatty acid triesters of glycerol, called triglycerides. The word triacylglycerol is sometimes used synonymously with triglyceride, in these compounds, the three hydroxyl groups of glycerol are each esterified, typically by different fatty acids. Because they function as a store, these lipids comprise the bulk of storage fat in animal tissues. The hydrolysis of the bonds of triglycerides and the release of glycerol. Additional subclasses of glycerolipids are represented by glycosylglycerols, which are characterized by the presence of one or more sugar residues attached to glycerol via a glycosidic linkage, examples of structures in this category are the digalactosyldiacylglycerols found in plant membranes and seminolipid from mammalian sperm cells. Glycerophospholipids, usually referred to as phospholipids, are ubiquitous in nature and are key components of the bilayer of cells, as well as being involved in metabolism. Neural tissue contains high amounts of glycerophospholipids, and alterations in their composition has been implicated in various neurological disorders. Examples of glycerophospholipids found in biological membranes are phosphatidylcholine, phosphatidylethanolamine and phosphatidylserine, the major sphingoid base of mammals is commonly referred to as sphingosine
29.
Ion
–
An ion is an atom or a molecule in which the total number of electrons is not equal to the total number of protons, giving the atom or molecule a net positive or negative electrical charge. Ions can be created, by chemical or physical means. In chemical terms, if an atom loses one or more electrons. If an atom gains electrons, it has a net charge and is known as an anion. Ions consisting of only a single atom are atomic or monatomic ions, because of their electric charges, cations and anions attract each other and readily form ionic compounds, such as salts. In the case of ionization of a medium, such as a gas, which are known as ion pairs are created by ion impact, and each pair consists of a free electron. The word ion comes from the Greek word ἰόν, ion, going and this term was introduced by English physicist and chemist Michael Faraday in 1834 for the then-unknown species that goes from one electrode to the other through an aqueous medium. Faraday also introduced the words anion for a charged ion. In Faradays nomenclature, cations were named because they were attracted to the cathode in a galvanic device, arrhenius explanation was that in forming a solution, the salt dissociates into Faradays ions. Arrhenius proposed that ions formed even in the absence of an electric current, ions in their gas-like state are highly reactive, and do not occur in large amounts on Earth, except in flames, lightning, electrical sparks, and other plasmas. These gas-like ions rapidly interact with ions of charge to give neutral molecules or ionic salts. These stabilized species are commonly found in the environment at low temperatures. A common example is the present in seawater, which are derived from the dissolved salts. Electrons, due to their mass and thus larger space-filling properties as matter waves, determine the size of atoms. Thus, anions are larger than the parent molecule or atom, as the excess electron repel each other, as such, in general, cations are smaller than the corresponding parent atom or molecule due to the smaller size of its electron cloud. One particular cation contains no electrons, and thus consists of a single proton - very much smaller than the parent hydrogen atom. Since the electric charge on a proton is equal in magnitude to the charge on an electron, an anion, from the Greek word ἄνω, meaning up, is an ion with more electrons than protons, giving it a net negative charge. A cation, from the Greek word κατά, meaning down, is an ion with fewer electrons than protons, there are additional names used for ions with multiple charges
30.
Water
–
Water is a transparent and nearly colorless chemical substance that is the main constituent of Earths streams, lakes, and oceans, and the fluids of most living organisms. Its chemical formula is H2O, meaning that its molecule contains one oxygen, Water strictly refers to the liquid state of that substance, that prevails at standard ambient temperature and pressure, but it often refers also to its solid state or its gaseous state. It also occurs in nature as snow, glaciers, ice packs and icebergs, clouds, fog, dew, aquifers, Water covers 71% of the Earths surface. It is vital for all forms of life. Only 2. 5% of this water is freshwater, and 98. 8% of that water is in ice and groundwater. Less than 0. 3% of all freshwater is in rivers, lakes, and the atmosphere, a greater quantity of water is found in the earths interior. Water on Earth moves continually through the cycle of evaporation and transpiration, condensation, precipitation. Evaporation and transpiration contribute to the precipitation over land, large amounts of water are also chemically combined or adsorbed in hydrated minerals. Safe drinking water is essential to humans and other even though it provides no calories or organic nutrients. There is a correlation between access to safe water and gross domestic product per capita. However, some observers have estimated that by 2025 more than half of the population will be facing water-based vulnerability. A report, issued in November 2009, suggests that by 2030, in developing regions of the world. Water plays an important role in the world economy, approximately 70% of the freshwater used by humans goes to agriculture. Fishing in salt and fresh water bodies is a source of food for many parts of the world. Much of long-distance trade of commodities and manufactured products is transported by boats through seas, rivers, lakes, large quantities of water, ice, and steam are used for cooling and heating, in industry and homes. Water is an excellent solvent for a variety of chemical substances, as such it is widely used in industrial processes. Water is also central to many sports and other forms of entertainment, such as swimming, pleasure boating, boat racing, surfing, sport fishing, Water is a liquid at the temperatures and pressures that are most adequate for life. Specifically, at atmospheric pressure of 1 bar, water is a liquid between the temperatures of 273.15 K and 373.15 K
31.
Metal
–
A metal is a material that is typically hard, opaque, shiny, and has good electrical and thermal conductivity. Metals are generally malleable—that is, they can be hammered or pressed permanently out of shape without breaking or cracking—as well as fusible and ductile, about 91 of the 118 elements in the periodic table are metals, the others are nonmetals or metalloids. Some elements appear in both metallic and non-metallic forms, astrophysicists use the term metal to collectively describe all elements other than hydrogen and helium, the simplest two, in a star. The star fuses smaller atoms, mostly hydrogen and helium, to larger ones over its lifetime. In that sense, the metallicity of an object is the proportion of its matter made up of all chemical elements. Many elements and compounds that are not normally classified as metals become metallic under high pressures, the atoms of metallic substances are typically arranged in one of three common crystal structures, namely body-centered cubic, face-centered cubic, and hexagonal close-packed. In bcc, each atom is positioned at the center of a cube of eight others, in fcc and hcp, each atom is surrounded by twelve others, but the stacking of the layers differs. Some metals adopt different structures depending on the temperature, atoms of metals readily lose their outer shell electrons, resulting in a free flowing cloud of electrons within their otherwise solid arrangement. This provides the ability of metallic substances to easily transmit heat, while this flow of electrons occurs, the solid characteristic of the metal is produced by electrostatic interactions between each atom and the electron cloud. This type of bond is called a metallic bond, Metals are usually inclined to form cations through electron loss, reacting with oxygen in the air to form oxides over various timescales. Examples,4 Na + O2 →2 Na2O2 Ca + O2 →2 CaO4 Al +3 O2 →2 Al2O3, the transition metals are slower to oxidize because they form a passivating layer of oxide that protects the interior. Others, like palladium, platinum and gold, do not react with the atmosphere at all, some metals form a barrier layer of oxide on their surface which cannot be penetrated by further oxygen molecules and thus retain their shiny appearance and good conductivity for many decades. The oxides of metals are generally basic, as opposed to those of nonmetals, exceptions are largely oxides with very high oxidation states such as CrO3, Mn2O7, and OsO4, which have strictly acidic reactions. Painting, anodizing or plating metals are good ways to prevent their corrosion, however, a more reactive metal in the electrochemical series must be chosen for coating, especially when chipping of the coating is expected. Water and the two form an electrochemical cell, and if the coating is less reactive than the coatee. Metals in general have high conductivity, high thermal conductivity. Typically they are malleable and ductile, deforming under stress without cleaving, in terms of optical properties, metals are shiny and lustrous. Sheets of metal beyond a few micrometres in thickness appear opaque, although most metals have higher densities than most nonmetals, there is wide variation in their densities, lithium being the least dense solid element and osmium the densest
32.
Organic compound
–
An organic compound is virtually any chemical compound that contains carbon, although a consensus definition remains elusive and likely arbitrary. Organic compounds are rare terrestrially, but of importance because all known life is based on organic compounds. The most basic petrochemicals are considered the building blocks of organic chemistry, for historical reasons discussed below, a few types of carbon-containing compounds, such as carbides, carbonates, simple oxides of carbon, and cyanides are considered inorganic. The distinction between organic and inorganic compounds, while useful in organizing the vast subject of chemistry. Organic chemistry is the science concerned with all aspects of organic compounds, Organic synthesis is the methodology of their preparation. The word organic is historical, dating to the 1st century, for many centuries, Western alchemists believed in vitalism. This is the theory that certain compounds could be synthesized only from their classical elements—earth, water, air, vitalism taught that these organic compounds were fundamentally different from the inorganic compounds that could be obtained from the elements by chemical manipulation. Vitalism survived for a while even after the rise of modern atomic theory and it first came under question in 1824, when Friedrich Wöhler synthesized oxalic acid, a compound known to occur only in living organisms, from cyanogen. A more decisive experiment was Wöhlers 1828 synthesis of urea from the inorganic salts potassium cyanate, urea had long been considered an organic compound, as it was known to occur only in the urine of living organisms. Wöhlers experiments were followed by others, in which increasingly complex organic substances were produced from inorganic ones without the involvement of any living organism. Even though vitalism has been discredited, scientific nomenclature retains the distinction between organic and inorganic compounds, still, even the broadest definition requires excluding alloys that contain carbon, including steel. The C-H definition excludes compounds that are considered organic, neither urea nor oxalic acid is organic by this definition, yet they were two key compounds in the vitalism debate. The IUPAC Blue Book on organic nomenclature specifically mentions urea and oxalic acid, other compounds lacking C-H bonds but traditionally considered organic include benzenehexol, mesoxalic acid, and carbon tetrachloride. Mellitic acid, which contains no C-H bonds, is considered an organic substance in Martian soil. The C-H bond-only rule also leads to somewhat arbitrary divisions in sets of carbon-fluorine compounds, for example, CF4 would be considered by this rule to be inorganic, whereas CF3H would be organic. Organic compounds may be classified in a variety of ways, one major distinction is between natural and synthetic compounds. Another distinction, based on the size of organic compounds, distinguishes between small molecules and polymers, natural compounds refer to those that are produced by plants or animals. Many of these are extracted from natural sources because they would be more expensive to produce artificially
33.
Amino acid
–
Amino acids are organic compounds containing amine and carboxyl functional groups, along with a side chain specific to each amino acid. The key elements of an acid are carbon, hydrogen, oxygen. About 500 amino acids are known and can be classified in many ways, in the form of proteins, amino acids comprise the second-largest component of human muscles, cells and other tissues. Outside proteins, amino acids perform critical roles in such as neurotransmitter transport. In biochemistry, amino acids having both the amine and the acid groups attached to the first carbon atom have particular importance. They are known as 2-, alpha-, or α-amino acids and they include the 22 proteinogenic amino acids, which combine into peptide chains to form the building-blocks of a vast array of proteins. These are all L-stereoisomers, although a few D-amino acids occur in bacterial envelopes, as a neuromodulator, twenty of the proteinogenic amino acids are encoded directly by triplet codons in the genetic code and are known as standard amino acids. The other two are selenocysteine, and pyrrolysine, pyrrolysine and selenocysteine are encoded via variant codons, for example, selenocysteine is encoded by stop codon and SECIS element. N-formylmethionine is generally considered as a form of methionine rather than as a separate proteinogenic amino acid, codon–tRNA combinations not found in nature can also be used to expand the genetic code and create novel proteins known as alloproteins incorporating non-proteinogenic amino acids. Many important proteinogenic and non-proteinogenic amino acids also play critical roles within the body. Nine proteinogenic amino acids are called essential for humans because they cannot be created from other compounds by the human body, others may be conditionally essential for certain ages or medical conditions. Essential amino acids may also differ between species, because of their biological significance, amino acids are important in nutrition and are commonly used in nutritional supplements, fertilizers, and food technology. Industrial uses include the production of drugs, biodegradable plastics, the first few amino acids were discovered in the early 19th century. In 1806, French chemists Louis-Nicolas Vauquelin and Pierre Jean Robiquet isolated a compound in asparagus that was subsequently named asparagine, cystine was discovered in 1810, although its monomer, cysteine, remained undiscovered until 1884. Glycine and leucine were discovered in 1820, usage of the term amino acid in the English language is from 1898. Proteins were found to yield amino acids after enzymatic digestion or acid hydrolysis, in the structure shown at the top of the page, R represents a side chain specific to each amino acid. The carbon atom next to the group is called the α–carbon. Amino acids containing an amino group bonded directly to the alpha carbon are referred to as amino acids
34.
Protein biosynthesis
–
Protein synthesis is the process whereby biological cells generate new proteins, it is balanced by the loss of cellular proteins via degradation or export. Protein biosynthesis is regulated at multiple steps. They are principally during transcription and translation, the cistron DNA is transcribed into the first of a series of RNA intermediates. The last version is used as a template in synthesis of a polypeptide chain, Protein will often be synthesized directly from genes by translating mRNA. However, when a protein must be available on short notice or in large quantities, a proprotein is an inactive protein containing one or more inhibitory peptides that can be activated when the inhibitory sequence is removed by proteolysis during posttranslational modification. A preprotein is a form that contains a sequence that specifies its insertion into or through membranes. The signal peptide is cleaved off in the endoplasmic reticulum, preproproteins have both sequences still present. The amino acids are linked together to extend the growing protein chain. This whole complex of processes is carried out by the ribosome, the ribosome latches onto the end of an mRNA molecule and moves along it, capturing loaded tRNA molecules and joining together their amino acids to form a new protein chain. Protein biosynthesis, although similar, is different for prokaryotes and eukaryotes. In transcription an mRNA chain is generated, with one strand of the DNA double helix in the genome as a template and this strand is called the template strand. Transcription occurs in the nucleus, where the DNA is held. The DNA structure of the cell is made up of two made up of sugar and phosphate held together by hydrogen bonds between the bases of opposite strands. The sugar and the phosphate in each strand are joined together by stronger covalent bonds. The DNA is unzipped by the helicase, leaving the single nucleotide chain open to be copied. RNA polymerase reads the DNA strand from the 3-prime end to the 5-prime end, the general RNA structure is very similar to the DNA structure, but in RNA the nucleotide uracil takes the place that thymine occupies in DNA. The single strand of mRNA leaves the nucleus through nuclear pores, hnRNA then undergoes splicing of introns via spliceosomes to produce the final mRNA. The synthesis of proteins from RNA is known as translation, in eukaryotes, translation occurs in the cytoplasm, where the ribosomes are located
35.
Medicine
–
Medicine is the science and practice of the diagnosis, treatment, and prevention of disease. The word medicine is derived from Latin medicus, meaning a physician, Medicine encompasses a variety of health care practices evolved to maintain and restore health by the prevention and treatment of illness. Medicine has existed for thousands of years, during most of which it was an art frequently having connections to the religious and philosophical beliefs of local culture. For example, a man would apply herbs and say prayers for healing, or an ancient philosopher. In recent centuries, since the advent of modern science, most medicine has become a combination of art, while stitching technique for sutures is an art learned through practice, the knowledge of what happens at the cellular and molecular level in the tissues being stitched arises through science. Prescientific forms of medicine are now known as medicine and folk medicine. They remain commonly used with or instead of medicine and are thus called alternative medicine. For example, evidence on the effectiveness of acupuncture is variable and inconsistent for any condition, in contrast, treatments outside the bounds of safety and efficacy are termed quackery. Medical availability and clinical practice varies across the world due to differences in culture. In modern clinical practice, physicians personally assess patients in order to diagnose, treat, the doctor-patient relationship typically begins an interaction with an examination of the patients medical history and medical record, followed by a medical interview and a physical examination. Basic diagnostic medical devices are typically used, after examination for signs and interviewing for symptoms, the doctor may order medical tests, take a biopsy, or prescribe pharmaceutical drugs or other therapies. Differential diagnosis methods help to rule out conditions based on the information provided, during the encounter, properly informing the patient of all relevant facts is an important part of the relationship and the development of trust. The medical encounter is then documented in the record, which is a legal document in many jurisdictions. Follow-ups may be shorter but follow the general procedure. The diagnosis and treatment may take only a few minutes or a few weeks depending upon the complexity of the issue, the components of the medical interview and encounter are, Chief complaint, the reason for the current medical visit. They are in the patients own words and are recorded along with the duration of each one, also called chief concern or presenting complaint. History of present illness, the order of events of symptoms. Distinguishable from history of illness, often called past medical history
36.
Nutrition
–
Nutrition is the science that interprets the interaction of nutrients and other substances in food in relation to maintenance, growth, reproduction, health and disease of an organism. It includes food intake, absorption, assimilation, biosynthesis, catabolism, the diet of an organism is what it eats, which is largely determined by the availability, the processing and palatability of foods. A healthy diet includes preparation of food and storage methods that preserve nutrients from oxidation, heat or leaching, and they also provide preventive and therapeutic programs at work places, schools and similar institutions. Government regulation especially in terms of licensing, is less universal for the CCN than that of RD or RDN. Another advanced Nutrition Professional is a Certified Nutrition Specialist or CNS and these Board Certified Nutritionists typically specialize in obesity and chronic disease. In order to become certified, potential CNS candidate must pass an examination. This exam covers specific domains within the health sphere including, Clinical Intervention, a poor diet can cause the wasting of kwashiorkor in acute cases, and the stunting of marasmus in chronic cases of malnutrition. The first recorded dietary advice, carved into a Babylonian stone tablet in about 2500 BC, scurvy, later found to be a vitamin C deficiency, was first described in 1500 BC in the Ebers Papyrus. According to Walter Gratzer, the study of nutrition probably began during the 6th century BC, in China, the concept of Qi developed, a spirit or wind similar to what Western Europeans later called pneuma. Food was classified into hot and cold in China, India, Malaya, humours developed perhaps first in China alongside qi. Ho the Physician concluded that diseases are caused by deficiencies of elements, the first recorded nutritional experiment with human subjects is found in the Bibles Book of Daniel. Daniel and his friends were captured by the king of Babylon during an invasion of Israel, selected as court servants, they were to share in the kings fine foods and wine. But they objected, preferring vegetables and water in accordance with their Jewish dietary restrictions, the kings chief steward reluctantly agreed to a trial. Daniel and his friends received their diet for ten days and were compared to the kings men. Appearing healthier, they were allowed to continue with their diet, around 475 BC, Anaxagoras stated that food is absorbed by the human body and, therefore, contains homeomerics, suggesting the existence of nutrients. Around 400 BC, Hippocrates, who recognized and was concerned with obesity, the works that are still attributed to him, Corpus Hippocraticum, called for moderation and emphasized exercise. Salt, pepper and other spices were prescribed for various ailments in various preparations for example mixed with vinegar, in the 2nd century BC, Cato the Elder believed that cabbage could cure digestive diseases, ulcers, warts, and intoxication. Living about the turn of the millennium, Aulus Celsus, an ancient Roman doctor, believed in strong and weak foods
37.
Agriculture
–
Agriculture is the cultivation and breeding of animals, plants and fungi for food, fiber, biofuel, medicinal plants and other products used to sustain and enhance human life. Agriculture was the key development in the rise of human civilization. The study of agriculture is known as agricultural science, the history of agriculture dates back thousands of years, and its development has been driven and defined by greatly different climates, cultures, and technologies. Industrial agriculture based on large-scale monoculture farming has become the dominant agricultural methodology, genetically modified organisms are an increasing component of agriculture, although they are banned in several countries. Agricultural food production and water management are increasingly becoming global issues that are fostering debate on a number of fronts, the major agricultural products can be broadly grouped into foods, fibers, fuels, and raw materials. Specific foods include cereals, vegetables, fruits, oils, meats, fibers include cotton, wool, hemp, silk and flax. Raw materials include lumber and bamboo, other useful materials are also produced by plants, such as resins, dyes, drugs, perfumes, biofuels and ornamental products such as cut flowers and nursery plants. The word agriculture is a late Middle English adaptation of Latin agricultūra, from ager, field, Agriculture usually refers to human activities, although it is also observed in certain species of ant, termite and ambrosia beetle. To practice agriculture means to use resources to produce commodities which maintain life, including food, fiber, forest products, horticultural crops. This definition includes arable farming or agronomy, and horticulture, all terms for the growing of plants, even then, it is acknowledged that there is a large amount of knowledge transfer and overlap between silviculture and agriculture. In traditional farming, the two are often combined even on small landholdings, leading to the term agroforestry, Agriculture began independently in different parts of the globe, and included a diverse range of taxa. At least 11 separate regions of the Old and New World were involved as independent centers of origin, wild grains were collected and eaten from at least 105,000 years ago. Pigs were domesticated in Mesopotamia around 15,000 years ago, rice was domesticated in China between 13,500 and 8,200 years ago, followed by mung, soy and azuki beans. Sheep were domesticated in Mesopotamia between 13,000 and 11,000 years ago. From around 11,500 years ago, the eight Neolithic founder crops, emmer and einkorn wheat, hulled barley, peas, lentils, bitter vetch, chick peas and flax were cultivated in the Levant. Cattle were domesticated from the aurochs in the areas of modern Turkey. In the Andes of South America, the potato was domesticated between 10,000 and 7,000 years ago, along with beans, coca, llamas, alpacas, sugarcane and some root vegetables were domesticated in New Guinea around 9,000 years ago. Sorghum was domesticated in the Sahel region of Africa by 7,000 years ago, cotton was domesticated in Peru by 5,600 years ago, and was independently domesticated in Eurasia at an unknown time
38.
Pharmaceutical drug
–
A pharmaceutical drug is a drug used to diagnose, cure, treat, or prevent disease. Drug therapy is an important part of the field and relies on the science of pharmacology for continual advancement. Drugs are classified in various ways, one of the key divisions is by level of control, which distinguishes prescription drugs from over-the-counter drugs. Other ways to classify medicines are by mode of action, route of administration, biological system affected, an elaborate and widely used classification system is the Anatomical Therapeutic Chemical Classification System. The World Health Organization keeps a list of essential medicines, Drug discovery and drug development are complex and expensive endeavors undertaken by pharmaceutical companies, academic scientists, and governments. Governments generally regulate what drugs can be marketed, how drugs are marketed, controversies have arisen over drug pricing and disposal of used drugs. In the US, a drug is, A substance recognized by an official pharmacopoeia or formulary, a substance intended for use in the diagnosis, cure, mitigation, treatment, or prevention of disease. A substance intended to affect the structure or any function of the body, a substance intended for use as a component of a medicine but not a device or a component, part or accessory of a device. Pharmaceutical or a drug is classified on the basis of their origin, Drug from natural origin, Herbal or plant or mineral origin, some drug substances are of marine origin. Drug from chemical as well as origin, Derived from partial herbal and partial chemical synthesis Chemical. Drug derived from animal origin, For example, hormones, Drug derived from microbial origin, Antibiotics Drug derived by biotechnology genetic-engineering, hybridoma technique for example Drug derived from radioactive substances. An elaborate and widely used system is the Anatomical Therapeutic Chemical Classification System. The World Health Organization keeps a list of essential medicines, the main classes of painkillers are NSAIDs, opioids and Local anesthetics. For consciousness Some anesthetics include Benzodiazepines and Barbiturates, the main categories of drugs for musculoskeletal disorders are, NSAIDs, muscle relaxants, neuromuscular drugs, and anticholinesterases. Euthanasia is not permitted by law in countries, and consequently medicines will not be licensed for this use in those countries. Administration is the process by which a patient takes a medicine, there are three major categories of drug administration, enteral, parenteral, and other. It can be performed in various forms such as pills, tablets. There are many variations in the routes of administration, including intravenous and they can be administered all at once as a bolus, at frequent intervals or continuously
39.
Disease
–
A disease is a particular abnormal condition, a disorder of a structure or function, that affects part or all of an organism. The study of disease is called pathology which includes the study of cause, Disease is often construed as a medical condition associated with specific symptoms and signs. When caused by pathogens, even in the literature, the term disease is often misleadingly used in the place of its causal agent. This language habitat can cause confusion in the communication of the principle in epidemiology. Diseases can affect not only physically, but also emotionally. Death due to disease is called death by natural causes, there are four main types of disease, infectious diseases, deficiency diseases, genetic diseases, and physiological diseases. Diseases can also be classified as communicable and non-communicable, the deadliest diseases in humans are coronary artery disease, followed by cerebrovascular disease and lower respiratory infections. In many cases, terms such as disease, disorder, morbidity, there are situations, however, when specific terms are considered preferable. Disease The term disease broadly refers to any condition that impairs the normal functioning of the body, for this reason, diseases are associated with dysfunctioning of the bodys normal homeostatic processes. The term disease has both a count sense and a noncount sense, by contrast, an infection that is asymptomatic during its incubation period, but expected to produce symptoms later, is usually considered a disease. Non-infectious diseases are all other diseases, including most forms of cancer, heart disease, acquired disease disease that began at some point during ones lifetime, as opposed to disease that was already present at birth, which is congenital disease. Acquired sounds like it could mean caught via contagion, but it simply means acquired sometime after birth and it also sounds like it could imply secondary disease, but acquired disease can be primary disease. It is often, genetic and can be inherited and it can also be the result of a vertically transmitted infection from the mother such as HIV/AIDS. Genetic disease disease that is caused by genetic mutation and it is often inherited, but some mutations are random and de novo. Hereditary or inherited disease a type of disease caused by mutation that is hereditary Iatrogenic disease A disease condition caused by medical intervention. Idiopathic disease disease whose cause is unknown, as medical science has advanced, many diseases whose causes were formerly complete mysteries have been somewhat explained or even extensively explained. Bacterial infections can be primary or secondary to a viral infection or burn. Terminal disease disease with death as an inevitable result Illness Illness is generally used as a synonym for disease, however, this term is occasionally used to refer specifically to the patients personal experience of his or her disease
40.
Soil
–
Soil is a mixture of minerals, organic matter, gases, liquids, and countless organisms that together support life on Earth. Soil is called the Skin of the Earth and interfaces with the lithosphere, the hydrosphere, the atmosphere, the term pedolith, used commonly to refer to the soil, literally translates ground stone. Soil consists of a phase of minerals and organic matter, as well as a porous phase that holds gases. Accordingly, soils are often treated as a system of solids, liquids. Soil is a product of the influence of climate, relief, organisms, Soil continually undergoes development by way of numerous physical, chemical and biological processes, which include weathering with associated erosion. Given its complexity and strong internal connectedness soil has been considered as an ecosystem by soil ecologists. Most soils have a dry bulk density between 1.1 and 1.6 g/cm3, while the particle density is much higher. Little of the soil of planet Earth is older than the Pleistocene and none is older than the Cenozoic, Soil science has two basic branches of study, edaphology and pedology. Edaphology is concerned with the influence of soils on living things, pedology is focused on the formation, description, and classification of soils in their natural environment. In engineering terms, soil is referred to as regolith, or loose material that lies above the solid geology. Soil is commonly referred to as earth or dirt, technically, as soil resources serve as a basis for food security, the international community advocates its sustainable and responsible use through different types of soil governance. Soil is a component of the Earths ecosystem. The worlds ecosystems are impacted in far-reaching ways by the carried out in the soil, from ozone depletion and global warming, to rainforest destruction. Following the atmosphere, the soil is the next largest carbon reservoir on Earth, as the planet warms, soils will add carbon dioxide to the atmosphere due to its increased biological activity at higher temperatures. Thus, soil carbon losses likely have a positive feedback response to global warming. Since soil has a range of available niches and habitats. A gram of soil can contain billions of organisms, belonging to thousands of species, mostly microbial, Soil has a mean prokaryotic density of roughly 108 organisms per gram, whereas the ocean has no more than 107 procaryotic organisms per milliliter of seawater. Since plant roots need oxygen, ventilation is an important characteristic of soil and this ventilation can be accomplished via networks of interconnected soil pores, which also absorb and hold rainwater making it readily available for plant uptake
41.
Fertilizer
–
A fertilizer or fertiliser is any material of natural or synthetic origin that is applied to soils or to plant tissues to supply one or more plant nutrients essential to the growth of plants. Fertilizers enhance the growth of plants and this goal is met in two ways, the traditional one being additives that provide nutrients. The second mode by which some fertilizers act is to enhance the effectiveness of the soil by modifying its water retention and aeration and this article, like many on fertilizers, emphasises the nutritional aspect. The nutrients required for plant life are classified according to the elements. Instead compounds containing these elements are the basis of fertilizers, the macronutrients are consumed in larger quantities and are present in plant tissue in quantities from 0. 15% to 6. 0% on a dry matter basis. Plants are made up of four elements, hydrogen, oxygen, carbon. Carbon, hydrogen and oxygen are widely available as water and carbon dioxide, although nitrogen makes up most of the atmosphere, it is in a form that is unavailable to plants. Nitrogen is the most important fertilizer since nitrogen is present in proteins, DNA, to be nutritious to plants, nitrogen must be made available in a fixed form. Only some bacteria and their host plants can fix atmospheric nitrogen by converting it to ammonia, phosphate is required for the production of DNA and ATP, the main energy carrier in cells, as well as certain lipids. Micronutrients are consumed in quantities and are present in plant tissue on the order of parts-per-million, ranging from 0.15 to 400 ppm DM. These elements are present at the active sites of enzymes that carry out the plants metabolism. Because these elements enable catalysts their impact far exceeds their weight percentage, Fertilizers are classified in several ways. They are classified according to whether they provide a single nutrient, multinutrient fertilizers provide two or more nutrients, for example N and P. Fertilizers are also sometimes classified as inorganic versus organic. Inorganic fertilizers exclude carbon-containing materials except ureas, organic fertilizers are usually plant- or animal-derived matter. Inorganic are sometimes called synthetic fertilizers since various chemical treatments are required for their manufacture, the main nitrogen-based straight fertilizer is ammonia or its solutions. Ammonium nitrate is widely used. Urea is another source of nitrogen, having the advantage that it is solid and non-explosive, unlike ammonia and ammonium nitrate. A few percent of the fertilizer market has been met by calcium ammonium nitrate
42.
Pest control
–
Pest control refers to the regulation or management of a species defined as a pest, and can be perceived to be detrimental to a persons health, the ecology or the economy. A practitioner of pest control is called an exterminator, Pest control is at least as old as agriculture, as there has always been a need to keep crops free from pests. In order to maximize production, it is advantageous to protect crops from competing species of plants. Techniques such as rotation, companion planting, and the selective breeding of pest-resistant cultivars have a long history. In the UK, following concern about animal welfare, humane pest control, for instance, with the urban red fox which territorial behaviour is used against the animal, usually in conjunction with non-injurious chemical repellents. In rural areas of Britain, the use of firearms for pest control is quite common, chemical pesticides date back 4,500 years, when the Sumerians used sulfur compounds as insecticides. The Rig Veda, which is about 4,000 years old, in the 20th century, the discovery of several synthetic insecticides, such as DDT, and herbicides boosted this development. Many pests have only become a problem as a result of the actions by humans. Modifying these actions can often reduce the pest problem. In the United States, raccoons caused a nuisance by tearing open refuse sacks, many householders introduced bins with locking lids, which deterred the raccoons from visiting. House flies tend to accumulate wherever there is activity and live in close association with people all over the world especially where food or food waste is exposed. Similarly, seagulls have become pests at many seaside resorts, tourists would often feed the birds with scraps of fish and chips, and before long, the birds would rely on this food source and act aggressively towards humans. Living organisms evolve and increase their resistance to biological, chemical, physical or any form of control. Perhaps as far ago as 3000BC in Egypt, cats were being used to control pests of grain such as rodents. In 1939/40 a survey discovered that cats could keep a population of rats down to a low level. However, if the rats were cleared by trapping or poisoning, ferrets were domesticated at least by 500 AD in Europe, being used as mousers. Mongooses have been introduced into homes to control rodents and snakes, biological pest control is the control of one through the control and management of natural predators and parasites. For example, mosquitoes are often controlled by putting Bt Bacillus thuringiensis ssp. israelensis, the treatment has no known negative consequences on the remaining ecology and is safe for humans to drink
_and_Carl_Ferdinand_Cori.jpg)
.
